DivisionEvent

DivisionEvent(
    duration: Duration | None = None,
    shape: DivisionShape | None = None,
)

A division between one stretch of a line and the next: in WSMN, a bar line. It sits in the NEXT chain like any event and has zero duration; it cannot be given one.

Divisions are optional and belong to the line they are in. An author may place all of them, some, or none, and different lines may divide differently (polymetric voices, early music). Nothing is measure-based: a pickup is simply a division that arrives early. A renderer that derives bar lines from a time signature fills the gaps and warns where an explicit division disagrees.

shape is how the division is drawn, in the notation system’s own vocabulary (BarLineShape for WSMN); None means a division whose drawing is unspecified. Repeat dots in a shape are visual only: whether anything repeats is the business of control flow, which follows the same rule (explicit wins, derived fills gaps, mismatch warns).

>>> from openmusickit.systems.wsmn.scoring.symbols import end_repeat
>>> DivisionEvent(shape=end_repeat)
DivisionEvent(shape=BarLineShape(BarLineComponent.DOTS, BarLineComponent.THIN, BarLineComponent.THICK))
>>> DivisionEvent().shape is None
True
>>> isinstance(DivisionEvent().duration, ZeroDuration)
True
>>> DivisionEvent(duration=None)
Traceback (most recent call last):
...
TypeError: ...
>>> from openmusickit.systems.wsmn.temporal.symbols import quarter
>>> DivisionEvent().duration = quarter
Traceback (most recent call last):
...
ValueError: A DivisionEvent has zero duration; it cannot be given MetricalDuration(1, 4).

Marks attach to a division as to any node; a segno or a fermata on a bar line is a Marking with a MARKS edge to it:

>>> from openmusickit.graph.edge import EdgeType
>>> from openmusickit.graph.graph import GraphMeta, OmkGraph
>>> from openmusickit.objects.marking import Marking
>>> from openmusickit.systems.wsmn.scoring.symbols import segno
>>> graph = OmkGraph(GraphMeta())
>>> division, sign = DivisionEvent(), Marking(mark=segno)
>>> graph.add_node(division)
>>> graph.add_node(sign)
>>> graph.add_edge(sign, division, EdgeType.MARKS)
>>> graph.get_edge(sign, division, EdgeType.MARKS).type
<EdgeType.MARKS: 'marks'>

Raises

Name	Type	Description
	ValueError	if duration is assigned anything but a ZeroDuration.

Attributes

Name	Description
meta
id
shape
duration

Methods

Name	Description
alter_duration
__setattr__

alter_duration

alter_duration(operation: Callable[[Duration, Any], Duration], operand: Any)

__setattr__

__setattr__(name: str, value: Any)